Cercospora Exochordicola — a New Hyphomycete Species from Russia

МИКОЛОГИЯ И ФИТОПАТОЛОГИЯ Том 43 2009 Вып.2

БИОРАЗНООБРАЗИЕ, СИСТЕМАТИКА, ЭКОЛОГИЯ

УДК 582.288

БРАУН У., БУЛГАКОВ Т. С. CERCOSPORA EXOCHORDICOLA — НОВЫЙ ВИД ГИФОМИЦЕТА ИЗ РОССИИ

Braun and Mel’nik (1997) published an annotated checklist of cercosporoid hyphomycetes (Capnodiales, Mycosphaerellaceae, Mycosphaerella Johanson anamorphs) of Russia. A world-wide checklist of names assigned to Cercospora Fresen. and Passalora Fr. and a survey of the current taxonomy based on phylogenetic examinations was issued by Crous and Braun (2003). Nevertheless the knowledge about these fungi in Russia and worldwide is still fragmentary. A new leaf-spotting cercosporoid hyphomycete has recently been found in the Botanical Garden of the Southern Federal University, Rostov-on-Don, Russia. Cercospora exochordicola U. Braun et Bulgakov sp. nov. MycoBank, MB 512611. Differt a Cercospora exochordae stromatibus majoribus, 10—70 mkm diam., conidio- phoris brevioribus, (5—)10—30 mkm longis, et conidiis obclavatis-fusiformibus, brevioribus, (20—)25—40(—50) mkm longis, 0—3-septatis. Holotype:OnExochorda racemosa (Lindl.) Rehd. (Rosaceae), Russia, Rostov region, Rostov-on-Don, Botanical garden of the Southern Federal University, 24 Sept. 2006, T. S. Bulgakov (HAL 2291 F). Leaf spots amphigenous, subcircular to angular-irregular, 1—3 mm diam., brown, centre becoming dingy grey, greyish white to white, surrounded by a narrow to broad brown margin or halo. Caespituli epiphyllous, punctiform to subeffuse, medium to dark brown. Mycelium internal; stromata immersed, 10—70 mkm diam., brown, composed of swollen hyphal cells, 2—6 mkm diam. Conidiophores in small to usually rather large fascicles, loose to moderately dense, arising from stromata, erumpent, erect, straight and subcylindrical to moderately geniculate-sinuous, unbranched, (5—)10—30%3—7 mkm, 0—1-septate, light brown to golden-brown, wall 0.5—1 mkm wide, smooth; conidiogenous cells integrated, terminal or conidiophores mostly reduced to conidiogenous cells, 5—25 mkm long, with 1—4 conspicuous conidiogenous loci, circular in front view, thickened and darkened, (1—)1.5—2 mkm diam. Conidia solitary, narrowly obclavate-fusiform, (20—)25— 40(—50)%2—4(—5) mkm, 0—3-septate, apex subacute, base obconically truncate, rarely truncate, hila somewhat thickened and darkened, 1—2 mkm wide (Fig.). Discussion:Exochorda racemosa (= E. grandiflora (Hook.) Lindl.), an Asian species distributed in eastern China (Roloff, Bдrtels, 2006), is a common ornamental shrub, and an

1 Martin-Luther-University, Institute of Biology, Geobotany and Botanical Garden, Herbarium, Neuwerk 21, D-06099 Halle (Saale), Germany. 2 Southern Scientific Centre of the Russian Academy of Sciences, Chekhov pr., 41, 344006 Rostov-on-Don, Russia; e-mail: [email protected].

81 C. exochordicola: a — fascicle of conidiophores, b — conidiophores, c — conidia. Scale — 10 mkm. U. Bra- un del. introduced, partly invasive plant in eastern and south-eastern parts of the USA. However, within its natural area no cercosporoid hyphomycetes have been recorded (Guo et al., 2005). Cercospora exochordae Chupp et F. Stevens was described on this host in Chupp (1954), based on a collection from North America (USA, Alabama). Crous and Braun (2003) examined type material of this species and reduced it to synonymy with Cercospora apii Fre- sen. s. lat. The stromata are small, 15—35 mkm diam., giving rise to fasciculate conidiophores, 30—200%3—5 mkm, and solitary, acicular, hyaline conidia with truncate base and a subacute apex, 30—150%2—4 mkm. Thus, C. exochordae is easily distinguishable from C. exochordicola. Among other Cercospora species on hosts of the Rosaceae, there is also no confusable species. Deighton (1987) introduced the combination Pseudocercospora exochordae (Chupp et F. Stevens) Deighton, but without any further details. The reasons for his combination are quite unclear since he did neither cite any collections examined, nor a description and illustration. Chupp and Stevens (in Chupp, 1954) described and depicted fasciculate conidiophores with acicular, hyaline conidia formed singly, but also superficial mycelium with solitary conidiophores. The latter structures cannot be part of the Cercospo- ra. Therefore, it is possible that the original material of C. exochordae was heterogeneous, but Crous and Braun (2003) only found the genuine Cercospora in type material. In case the type material will prove to be actually heterogeneous, the name C. exochordae has to be confined to the Cercospora element, as already done by Crous and Braun (2003).

REFERENCES

Braun U.,Mel’nik V.A.Cercosporoid fungi from Russia and adjacent countries / Proceed. Komarov. Bot. Inst. 1997. Vol. 20. P. 1—130 (in Russ.). Chupp C.Amonograph of the fungus genus Cercospora. Ithaca: Published by the author, 1954. 667 p.

82 Crous P.W.,Braun U.Mycosphaerella and its anamorphs. 1. Names published in Cercospora and Passalora / CBS Biodiversity Series. 2003. Vol. 1. P. 1—571. Deighton F.C.Newspecies of Pseudocercospora and Mycovellosiella, and new combinations into Pseudocercospora and Phaeoramularia / Trans. Brit. Mycol. Soc. 1987. Vol. 88. P. 365—391. G u o Y.-L., L i u X.-J., Hsieh W.-H.Flora Fungorum Sinicorum. Vol. 24. Cercospora. Beijing: Science Press, 1995. 373 p. Roloff A.,Bд rtels A.Flora der Gehцlze. Stuttgart: Eugen Ulmer Verlag, 2006. S. 1—844.

Martin-Luther-University Received 19 XI 2008 Halle (Saale), Germany Southern Scientific Centre Russian Academy of Sciences Rostov-on-Don, Russia [email protected]

РЕЗЮМЕ

Приводится описание нового для науки гифомицета Cercospora exochordicola, найденного на листьях Exochorda racemosa (Rosaceae) из ботанического сада Южного федерального уни- верситета (Ростов-на-Дону). Ключевые слова: микобиота России, анаморфные грибы, гифомицеты, Exochorda racemosa.

SUMMARY

Description of a new hyphomycete fungus Cercospora exochordicola which had been found on Exochorda racemosa from Botanical garden of the Southern Federal University (Rostov-on-Don). Key words: mycobiota of Russia, anamorphic fungi, hyphomycetes, Exochorda racemosa.